Răspuns:
m,apa=20g
c=36%
c=mdx100/ms, unde ms= md+m,apa
36/100= md/(md+20)
36(md+20)=100md----> md=11,25g piatra vanata
md1=40g
c1=10%
md2=80g
c2=40%
c3= md3x100/ms3
md3= md1+ md2= 120g
ms1=md1x100/c1= 40x100/10g=400g
ms2= 80x100/40g=200g
ms3=ms1+ms2=600
c3= 120x100/600= 20%
calculez c pentru solutia saturata
36g sare........(100+36)g sol
x.............................100g
x=c=26,5%
valoarea data c=30%>26,5% solutia data este saturata
Explicație: